AB0622 LUPUS NEPHRITIS: IS THE KIDNEY BIOPSY CURRENTLY NECESSARY IN THE MANAGEMENT OF LUPUS NEPHRITIS?
Authors: B. Issayeva, E. Aseeva, N. Nikishina, A. Mesnyankina, S. Solovyev, S. Issayeva, M. Saparbayeva, A. Amanzholova
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Lupus Nephritis (LN) is an immune-complex mediated glomerulonephritis affecting up to 60% of all SLE patients during the disease course. A kidney biopsy is indicated in SLE patients when proteinuria stably reaches or overcomes the level of 500 mg/24 h or spot urine protein to creatinine ratio (UPCR) &gt;500 mg/g (50 mg/mmol), especially with impaired renal function or active urinary sediment, and is generally recommended to evaluate the inflammatory findings but also to rule out other etiologies of renal involvement and to guide the need of immunosuppressive therapy. <h3>Objectives</h3> To investigate the histopathologic findings in first-time renal biopsies from SLE patients and evaluate the type and occurrence of histopathological findings other than LN as these may lead to a risk of inadequate therapeutic interventions. <h3>Methods</h3> 64 SLE patients who had a first-time onset of renal involvement from 24/11/2020 up to 24/10/2022 and subsequent renal biopsy were included in the study. All patients fulfilled the Systemic Lupus Erythematosus International Collaborating Clinics (SLICC) disease classification criteria (1) for SLE and were biopsied on clinical indication, i.e., proteinuria &gt; 0.5 g/day or active SLE in combination with a rise in plasma creatinine, decrease in glomerular function or new onset proteinuria with concurrent active urine sediment. <h3>Results</h3> In total, 64 patients (female 51 (76%), Male (15 (24%) with first time presentation of renal involvement who had been subject to renal biopsy were included.. The median age at the time of biopsy was 35,34± 11,19 years. For more patient baseline characteristics, see Table 1.Fifty two (81%) had findings consistent with LN according to ISN/RPS classification system [2]. Four patients (6 %) had class I - II, 19 (30%) -class III, 13 (20%) - class IV, 8 (12%) - Class V, 2 (3%) - Class VI, 3 (4%) - Class III ± V, 3 (4% - Class IV ± V. Tvelwe patients (19%) did not have histological changes in accordance with LN. Of these, 3 had thrombotic microangiopathy, 5 had IgA nephropathy, 4 were later found to be ANCA-positive and were re-diagnosed with concomitant ANCA-associated vasculitis. Of the 12 non-LN patients, all had proteinuria &gt; 0.5 g/day, 2 had new-onset low-grade proteinuria and concurrent active urine sediment, 2 had new-onset low-grade proteinuria with concurrent increasing SLE disease activity, and 5 patients had isolated persistent low-grade proteinuria. <h3>Conclusion</h3> We demonstrate that renal histopathology confirmed other causes than LN in a significant proportion (19 %) of SLE patients with signs of renal involvement. Since these patients may need other therapeutic interventions than patients with classic LN, we can conclude that the renal biopsy is important in order to guide the choice of therapeutics. <h3>References</h3> [1]Petri, M., et al. Derivation and validation of the Systemic Lupus International Collaborating Clinics classification criteria for systemic lupus erythematosus. Arthritis &amp; Rheumatism 64.8 (2012): 2677-2686. [2]Bajema, I et al.Revision of the International Society of Nephrology/Renal Pathology Society classification for lupus nephritis: clarification of definitions, and modified National Institutes of Health activity and chronicity indices. Kidney Int. 2018 Apr;93(4):789-796. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.